OTA Error LG G Stylo

So I recently rooted my phone which is on Android 5.0.2 (T Mobile LG-H631) , and unrooted it using universal unroot since supersu wouldn't unroot my phone for me, and now i want to ota update the phone but when when i do, it starts to say installing update, but ends up with an android bot and error written underneath. I'm new to the rooting world and regret rooting since i know little about flashing roms and such, and with that being said, would like a not too difficult solution for my problem. Thanks!